Micro and nanocarriers Micro and nanoscale technologies Oral drug delivery Tissue models Oral administration is a pillar of the pharmaceutical industry and yet it remains challenging to administer hydrophilic therapeutics by the oral route. Smart and controlled oral drug delivery could bypass the physiological barriers that limit the oral delivery of these therapeutics. Micro-and nanoscale technologies, with an unprecedented ability to create, control, and measure micro-or nanoenvironments, have found tremendous applications in biology and medicine. In particular, significant advances have been made in using these technologies for oral drug delivery. In this review, we briefly describe biological barriers to oral drug delivery and micro and nanoscale fabrication technologies. Micro and nanoscale drug carriers fabricated using these technologies, including bioadhesives, microparticles, micropatches, and nanoparticles, are described. Other applications of micro and nanoscale technologies are discussed, including fabrication of devices and tissue engineering models to precisely control or assess oral drug delivery in vivo and in vitro, respectively. Strategies to advance translation of micro and nanotechnologies into clinical trials for oral drug delivery are mentioned. Finally, challenges and future prospects on further integration of micro and nanoscale technologies with oral drug delivery systems are highlighted.

Understanding complex cell–cell interactions and physiological microenvironments is critical for the development of new therapies for treating human diseases. Current animal models fail to accurately predict success of therapeutic compounds and clinical treatments. Advances in biomaterials, engineering, and additive manufacturing have led to the development of printed tissues, lab-on-chip devices, and, more recently, organ-on-chip systems. These technologies have promising applications for the fabrication of more physiologically representative human tissues and can be used for high-throughput testing of human cells and organoids. These organ-on-chip systems can be fabricated with integrated fluidics to allow for the precise control and manipulation of cellular microenvironments with multiple cell types. Further control over these cellular environments can be achieved with bioprinting, allowing for three-dimensional (3D) printing of multiple materials and cell types to provide precisely controlled structures manufactured in a one-step process. As cell behavior is highly dependent on the physical and chemical properties of the environment, the behavior of cells in two-dimensional and 3D culture systems varies drastically. Providing devices that can support long-term cell culture and controlled stimulation of 3D culture systems will have a profound impact on the study of physiological processes and disease, as well as the development of new therapies. This review highlights recent advances in organ-on-chip systems and 3D bioprinting techniques for the development of in vitro physiological models.

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Cancer is one of the leading causes of death worldwide, despite the large efforts to improve the understanding of cancer biology and development of treatments. The attempts to improve cancer treatment are limited by the complexity of the local milieu in which cancer cells exist. The tumor microenvironment (TME) consists of a diverse population of tumor cells and stromal cells with immune constituents, microvasculature, extracellular matrix components, and gradients of oxygen, nutrients, and growth factors. The TME is not recapitulated in traditional models used in cancer investigation, limiting the translation of preliminary findings to clinical practice. Advances in 3D cell culture, tissue engineering, and microfluidics have led to the development of “cancer‐on‐a‐chip” platforms that expand the ability to model the TME in vitro and allow for high‐throughput analysis. The advances in the development of cancer‐on‐a‐chip platforms, implications for drug development, challenges to leveraging this technology for improved cancer treatment, and future integration with artificial intelligence for improved predictive drug screening models are discussed.